Let's turn this bug into something more general.
From an IRC talk: "the controls we have manipulate the orientation of the visualization, the controls I want put me in a spaceship flying around the visualization". An enhanced arcball and/or an alternate control system would be nice.

not bad. It's an extra range of motion that could be helpful for positioning. The roll is fixed about the center origin again though so at extreme ends of the page, the effect is much more pronounced. i.e., less precise.

As discussed on IRC, actually making this work properly would require a significant refactoring effort, to distinguish between a "model" and a "camera" (basically they're respective matrix transformations) in Tilt. Since this doesn't directly concern this bug, filed bug 734038.